Applications of yoga in oral oncology: A systematic scoping review

Abstract Background and Aims Yoga is well‐thought‐out as an all‐inclusive approach globally and can be administered in clinical care as an integrative or alternate approach to regular treatment. Yoga exercise has been disclosed to influence remission from cancer cells over a long period of time and also reverses epigenetic alterations. Applications of Yoga in the management of oral oncology patients are scarce, hence the need for a scoping review of the literature. Hence, this study aimed to conduct a scoping review of the existing empirical evidence on the applications of yoga in oral oncology. Methods The review methodology was informed by Joanna Brigg's Institute guidelines for systematic scoping reviews, and the review was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses extension for Scoping Reviews. Ten databases were searched. The records of all the literature retrieved from the search were imported into the Rayyan software for deduplication. After the full‐text screening, only two were found eligible for inclusion in the scoping review. Data obtained in the included literature were extracted and synthesized. Results This review found that Yoga was not significantly effective in the management of stress among oral cancer patients (p‐values > 0.04). However, it was found that Yoga significantly reduced anxiety, saliva stickiness, and episodes of falling ill (p‐values < 0.05) while it improved mental well‐being, cognitive functioning, emotional functioning, and head and neck pain of those oral cancer patients that received it (p‐values < 0.05). Conclusion An integrative care approach that considers nonpharmaceutical techniques such as yoga could help to reduce care cost while improving care outcomes and quality of life of oral cancer patients. Hence, it is imperative to consider yoga along with its potential benefits, and we recommend gradual incorporation of yoga into oral cancer care.


| INTRODUCTION
Oncology is the discipline of medicine that specializes in the diagnosis and management of cancers in the body, according to the US National Cancer Institute. 1 Cancer is a disorder whereby specific body's cells propagate hysterically and disseminate to other body parts. Oral cancer has been placed third globally after breast and lung cancers and within the head and neck region as the most frequent type of cancer. [2][3][4] Head and neck cancer, which includes the oral cancer, is the seventh commonest cancer worldwide, estimating for more than 660,000 fresh cases and 325,000 mortalities every year. 5 In the Asian continent, oral cancer is among the commonest types of cancers because of the high tobacco usage, betel quid chewing and excessive alcohol intake. Within Asia, prevalence likewise differs whereby the highest frequency was observed in Southern Asia exclusively in countries such as Bangladesh, Afghanistan, Sri Lanka, India, and Pakistan. 6 Europe is placed second after Asia in terms of incidence of oral cancer and rates also vary within the region. 7 In North America (Canada) and South America (Mexico), oral cancer is ranked as the twelfth and thirteenth most common cancer respectively, while in the United States, it is ranked the eleventh. 8 These global reports have shown consistently increasing trend in the frequency of oral cancer despite various interventions at the communal and hospital care levels by the authorities and nongovernmental agencies. 9 Regardless of evasion of disease-specific chance and dynamics as preventive measures, management strategies are also developing innovative techniques of improving quality of life of oral cancer patients. 10 Currently, surgery is regarded as the best approach for the management of oral cancer, 4,11 with adjuvant or neo-adjuvant chemoradiation to eliminate residual tumor or down-stage tumor before surgery. 12,13 Despite the combination of all preventive and treatment strategies, the quality of life of oral cancer patients still remains deprived. 14 This is because various factors affecting quality of life in oral cancer patients has not been adequately addressed by conventional preventive and management modalities. These factors include physical factors such as over-all well-being, discomfort, sleep quality and quantity, anxiety, exhaustion, and speech quality. 15,16 Other ancillary unaddressed factors may involve economic strains, issues with family support, protracted treatment phase, numerous clinic appointments, and illness relapse. 17 Despite all the powerful technologies and strong targeted medications for cancer patients which are very costly and associated with lethal side effects, the desired success still remains elusive for modern medicine. 14 Patients consequently may turn to nonconventional treatments such as complementary and alternative medicine (CAM). 18 Yoga, which comprises of a wide range of exercises is an element of CAM which steadily harmonizes the body and mind. 19 Yoga is well-thought-out as an all-inclusive approach globally which can be administered in medical care as a complementary or alternative approach to routine care. 20 Studies has shown that the practice of Yoga asanas, meditation and pranayamas can cutback carcinogenesis. 21 Additionally, Yoga exercise has been disclosed to positively impact on the long-term remission from cancer cells and it also helps reverses epigenetic alterations by DNA methylation, histone modifications, miRNAs and epi-transcriptomics. 22,23 Epigenetics which was first coined by Conrad Waddington in 1940 has undergone extensive study and mainly involves alterations in transcriptional expression and/or activity without variation in DNA sequence. 23 Applications of Yoga in the management of oral oncologic patients is scarce, hence the need for a scoping review of the literature.
Consequently, the key aim of this scoping review is to find out about existing literature on applications of Yoga in oral oncology management.

| METHODS
The Joanna Briggs Institute's guidelines for systematic scoping reviews (ScRs) informed the design of this ScR. 24 Also, the reportage of this ScR was informed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist. 25  The records of all the literature retrieved from the scoping search were imported into the Rayyan software for deduplication. 26 All duplicate records were removed. Thereafter, the deduplicated literatures were screened to exclude those literatures which are not relevant to the ScR question. The screening was done by two independent researchers, twostaged, and it was guided by a set of selection criteria. The first stage of the screening involved title and abstract screening while the second stage involved full text screening.
Only those literatures that met all of the following criteria were included in the ScR: peer-reviewed journal papers; papers published in English; papers reporting empirical findings on the application of yoga in the field of oral oncology; and papers with accessible full texts. However, all those literatures that do not meet all the above criteria were excluded from the ScR.
From the included literature, data were extracted using a customized data extraction sheet ( Table 1). The extraction sheet obtained information on the author names, year of publication, journal of publication, country where the study was conducted, sample characteristics, study design, study instrument, study outcomes, and conclusions. Only qualitative data synthesis was done on the extracted data-this involved the collation and summarization of the extracted data in a prose format. In this synthesis, relevant statistics were reported using mean (M), standard deviation (SD), and p-values, with a p-value < 0.05 considered to be of statistical significance. Quantitative data analysis (i.e., meta-analysis) was intended to be done; however, this could not be done due to the multiple heterogeneities in the methodology (research design, population characteristics, data analysis approach) of the included articles. 28

| RESULTS
From the 10 electronic databases searched, a total of 55 publications were retrieved. From these publications, six were duplicated copies and were all removed. After the screening of the titles and abstracts of the remaining 49 publications, 42 publications were excluded.
After the full text screening of the remaining seven publications, only two publications were finally included into the scoping review ( Figure 1; Table A4 [Appendix]).

| Country location, and authors, journals and years of publication of studies
The two studies were conducted in India, and had at least two authors, all of which were affiliated to institutions in India. 20

| Study design
Both studies were intervention-based. 20,27 However, the study by Bakshi and Goyal 20 adopted a randomized blinded trial design and with two compared groups while the other study, by Pattnaik et al., 27 was branded a prospective study with no compared group, that is, all the participants in the study were exposed to same intervention (yoga therapy).

| Sample characteristics
All the participants recruited into both studies were oral cancer patients. 20,27 None of the two studies reported data on the age distribution, culture, and religion of the participants. Also, only one study (by Bakshi and Goyal 20 ) reported data on the sociodemographic characteristics of their participants; the information included sex, locality, educational status, employment status, monthly family income, and addiction history.

| Duration of yoga intervention
The intervention in Bakshi & Goyal's study was a yoga therapy delivered in two phases: Phase 1 (before surgery) for a duration of 2 weeks; and Phase 2 (after wound healing has been achieved post-T A B L E 1 Data extraction sheet. surgery) for a duration of 2 months. 20 However, in the study by Pattnaik et al., 28 the intervention was a 1-month yoga training.

| Themes investigated and study instruments
The study by Bakshi and Goyal 20

| DISCUSSION
Medical pluralism, a combination of western and traditional medicine is a global practice. 29 Moreso for a degenerative disease, like cancer, people tend to use all sorts of traditional practices, especially in combination with modern medicine. 30,31 For instance, some medicinal herbs have been found to contribute positively to oral cancer treatment, which could signal opportunity for eventual development of new therapeutic strategies. 30 It has also been noted that the use of traditional methods for oral cancer treatment was common. 31 There are several conclusions that traditional medicine could be a significant and efficacious alternative in the treatment of oral cancers. 32,33 Hence, alternative medicine should be considered or integrated as part of national cancer management strategy. 33